Production of hGH with Synbio Introduction Problem: The human growth hormone used to be high in demand because it was needed to treat children with hypopituitary dwarfism, a disease where the pituitary gland does not produce enough hGH and the body is underdeveloped. It is also used to treat children with abnormal growth, helping them grow taller. Before this bacteria was developed, hGH was laboriously extracted from dead human bodies. This method was inefficient, expensive, and unsafe. In fact, patients injected with hGH sometimes developed the Creutzfeld-Jakob disease (a human form of mad cow disease) due to contamination.
Solution: In 1979, Genentech announced the first successful production of the human growth hormone through bacterial transformation. This allowed hGH to be manufactured in large quantities. Like insulin, the hGH project was a huge success.
What is human growth hormone?
HGH is a chain of 191 amino acids that is produced in the anterior pituitary gland, where released into the bloodstream. It is picked up by protein receptors on muscle and bone cells, making them grow and divide faster. There are two types of protein receptors that pick up hGH, and both receptors will be activated if there is enough hormone. This reaction causes the receptors to change shape and allow for more proteins like the insulin-like growth factor (which also promotes cell growth).
Engineering Bacteria to make hGH
Back to the central dogma of molecular biology, a gene is transcribed into mRNA, and mRNA is translated into a protein. hGH is created when the hGH gene is transcribed into mRNA and mRNA is translated into the hGH amino acid sequence. Engineers extract the mRNA after transcription and make a complementary strand of DNA called cDNA by matching base pairs. This way, introns (DNA that is not directly used in making the amino acids) are kept out. The cDNA is designed so that it has sticky ends that can connect to its vector, which is a piece of plasmid DNA that can be artificially manipulated. DNA ligase, an enzyme that helps connect DNA, is added so that the vector and complementary DNA are completely fused. The vector containing the recombinant DNA is put into E. coli by heat shocking, which makes the cell membranes permeable. The E. coli can then manufacture hGH through the normal processes of transcription and translation.
The two above vectors each contain a piece of recombinant cDNA linked to promoters naturally found in E. coli. As a result, RNA polymerase recognizes the promoter and transcribes the foreign DNA that codes for hGH. How is hGH incorrectly used?
Although hGH can be positively used to treat children with growth disorders, many others are taking hGH due to cosmetic reasons. Steroid companies package hGH in eye-catching containers, claiming that hGH removes wrinkles and increases muscle mass. However, many studies have shown that orally consuming hGH doesn't have any of these effects, as the stomach acids break down the hormone before it enters the bloodstream. If the protein does enter the bloodstream, additional hGH is not healthy for people who are no longer growing. For example, too much can cause enlarged limbs and tumors, as well other health problems. Human growth hormone should only be used if prescribed by a doctor.
Hello! My name is Elyse Cheng and I'm from Folsom, CA. I will be attending the Solano Community College for 8th grade this fall. My favorite subjects are biology and chemistry, as I love identifying their connections to our daily lives (I still don't know what I want to do in the future, though). I want to broaden my knowledge at camp and learn more about recent research in synthetic biology. Aside from academics, I also enjoy playing the piano and cello. I look forward to meeting everyone this summer!
Introduction
Problem: The human growth hormone used to be high in demand because it was needed to treat children with hypopituitary dwarfism, a disease where the pituitary gland does not produce enough hGH and the body is underdeveloped. It is also used to treat children with abnormal growth, helping them grow taller. Before this bacteria was developed, hGH was laboriously extracted from dead human bodies. This method was inefficient, expensive, and unsafe. In fact, patients injected with hGH sometimes developed the Creutzfeld-Jakob disease (a human form of mad cow disease) due to contamination.
Solution: In 1979, Genentech announced the first successful production of the human growth hormone through bacterial transformation. This allowed hGH to be manufactured in large quantities. Like insulin, the hGH project was a huge success.
What is human growth hormone?
HGH is a chain of 191 amino acids that is produced in the anterior pituitary gland, where released into the bloodstream. It is picked up by protein receptors on muscle and bone cells, making them grow and divide faster. There are two types of protein receptors that pick up hGH, and both receptors will be activated if there is enough hormone. This reaction causes the receptors to change shape and allow for more proteins like the insulin-like growth factor (which also promotes cell growth).
Engineering Bacteria to make hGH
Back to the central dogma of molecular biology, a gene is transcribed into mRNA, and mRNA is translated into a protein. hGH is created when the hGH gene is transcribed into mRNA and mRNA is translated into the hGH amino acid sequence. Engineers extract the mRNA after transcription and make a complementary strand of DNA called cDNA by matching base pairs. This way, introns (DNA that is not directly used in making the amino acids) are kept out. The cDNA is designed so that it has sticky ends that can connect to its vector, which is a piece of plasmid DNA that can be artificially manipulated. DNA ligase, an enzyme that helps connect DNA, is added so that the vector and complementary DNA are completely fused. The vector containing the recombinant DNA is put into E. coli by heat shocking, which makes the cell membranes permeable. The E. coli can then manufacture hGH through the normal processes of transcription and translation.
The two above vectors each contain a piece of recombinant cDNA linked to promoters naturally found in E. coli. As a result, RNA polymerase recognizes the promoter and transcribes the foreign DNA that codes for hGH.
How is hGH incorrectly used?
Although hGH can be positively used to treat children with growth disorders, many others are taking hGH due to cosmetic reasons. Steroid companies package hGH in eye-catching containers, claiming that hGH removes wrinkles and increases muscle mass. However, many studies have shown that orally consuming hGH doesn't have any of these effects, as the stomach acids break down the hormone before it enters the bloodstream. If the protein does enter the bloodstream, additional hGH is not healthy for people who are no longer growing. For example, too much can cause enlarged limbs and tumors, as well other health problems. Human growth hormone should only be used if prescribed by a doctor.
Sources
PowerPoint link:
https://docs.google.com/presentation/d/1-Ulp-RHB8d3CqxZy1XMv2GApeieEbPfhqbKPoIkh_nI/edit?usp=sharing
Hello! My name is Elyse Cheng and I'm from Folsom, CA. I will be attending the Solano Community College for 8th grade this fall. My favorite subjects are biology and chemistry, as I love identifying their connections to our daily lives (I still don't know what I want to do in the future, though). I want to broaden my knowledge at camp and learn more about recent research in synthetic biology. Aside from academics, I also enjoy playing the piano and cello. I look forward to meeting everyone this summer!